1. Field of the Invention
The present invention relates generally to a method and apparatus for blocking the flow of fluids through a pipe section. More particularly, the method and apparatus relates to the insertion of a cut-off blind member between the abutting flanges of a pipe joint in order to achieve the blocking off of fluid flow within the pipe.
2. The Prior Art
Various devices exist in the prior art for blinding off the flow of fluids within a pipe. However, these devices have consistently cut or severed the pipe section in some fashion so that a separate valve element or coupling component could be inserted into the severed pipe section.
For example, U.S. Pat. No. 3,703,906 to Tickett discloses a method and apparatus which includes a cutting element that is rotated around the pipe to sever a pipe section, through which a separate valve assembly is inserted.
U.S. Pat. No. 2,840,100 to Stephenson discloses an assembly which will accommodate the insertion of a tapping machine to form a hole through a pipe section. After the tapping machine is withdrawn from the assembly, separate gate members are then inserted into the interior of the overall assembly so that no gases can escape.
U.S. Pat. No. 3,863,667 to Ward includes a shearing member which cuts a section out of the pipe. Then, a separate piston member covers one pipe section to blind the flow of gases during repair. After the pipe is repaired, a housing assembly must be retained around the severed pipe section in order to maintain a seal once the flow of fluids is reestablished through the pipe. Similar assemblies are shown in U.S. Pat. Nos. 3,833,020 to Smith and 3,867,964 to Gardner.
U.S. Pat. No. 3,687,166 to Herrin likewise discloses an assembly which includes a component that severs a portion of the pipe section to accomplish the flow blockage effect.
Other prior art assemblies are shown by U.S. Pat. Nos. 2,600,497 to Hamer and 4,018,420 to Mueller, which disclose blinding assemblies for connection to a pipe. U.S. Pat. No. 4,119,115 to Carruthers discloses a flow cut-off assembly for use with plastic pipes, but again includes an element for cutting the pipe to establish the blind.
Accordingly, the prior art devices result in numerous disadvantages which are overcome by the present invention. For example, the prior art devices result in a costly operation because, generally, extensive equipment must be retained around the pipe after the flow blockage operation, in order to maintain a seal around the severed pipe section.